fix: eliminate error flash on startup by distinguishing loading from error state

- Change TQ_MIHOMO retryDelay from fixed 2000ms to exponential backoff
  (200ms → 400ms → 800ms, cap 3s) so core-dependent queries retry faster
- Expose isCoreDataPending from AppDataProvider to distinguish between
  data still loading vs actual errors
- ClashModeCard: show placeholder instead of "communication error" while
  core data is pending
- CurrentProxyCard: show empty space instead of "no active node" while
  core data is pending

src/providers/app-data-context.ts

@@ -16,6 +16,7 @@ export interface AppDataContextType {
   proxyProviders: Record<string, ProxyProvider>
   ruleProviders: Record<string, RuleProvider>
   systemProxyAddress: string
+  isCoreDataPending: boolean
 
   refreshProxy: () => Promise<any>
   refreshClashConfig: () => Promise<any>

src/providers/app-data-provider.tsx

@@ -23,7 +23,7 @@ const TQ_MIHOMO = {
   refetchOnReconnect: false,
   staleTime: 1500,
   retry: 3,
-  retryDelay: 2000,
+  retryDelay: (attempt: number) => Math.min(200 * 2 ** attempt, 3000),
 } as const
 
 const TQ_DEFAULTS = {
@@ -41,13 +41,21 @@ export const AppDataProvider = ({
 }) => {
   const { verge } = useVerge()
 
-  const { data: proxiesData, refetch: refreshProxy } = useQuery({
+  const {
+    data: proxiesData,
+    isPending: isProxiesPending,
+    refetch: refreshProxy,
+  } = useQuery({
     queryKey: ['getProxies'],
     queryFn: calcuProxies,
     ...TQ_MIHOMO,
   })
 
-  const { data: clashConfig, refetch: refreshClashConfig } = useQuery({
+  const {
+    data: clashConfig,
+    isPending: isClashConfigPending,
+    refetch: refreshClashConfig,
+  } = useQuery({
     queryKey: ['getClashConfig'],
     queryFn: getBaseConfig,
     ...TQ_MIHOMO,
@@ -323,6 +331,9 @@ export const AppDataProvider = ({
 
       systemProxyAddress: calculateSystemProxyAddress(),
 
+      // core 数据加载状态
+      isCoreDataPending: isProxiesPending || isClashConfigPending,
+
       // 刷新方法
       refreshProxy,
       refreshClashConfig,
@@ -335,6 +346,8 @@ export const AppDataProvider = ({
   }, [
     proxiesData,
     clashConfig,
+    isProxiesPending,
+    isClashConfigPending,
     rulesData,
     sysproxy,
     runningMode,